X-ray film



Filed Oct. 10.. 1947 TORNEY Patented Mar. 3, 1953 X-RAY FILM William Henecke and Samuel A. Herman, New York, N. Y.; said Henecke assignor to said Herman Application October 10, 1947, Serial No. 779,006

This invention relates to means and methods for marking photographic films, particularly dental X-ray films, so that they may be identified after development or prior thereto.

One object of the invention is to provide a film packet which does not require any careful etching or exposure to light prior to development and yet may permit of forming latent images of indicia which may be brought out during ordinary developing.

Another object is to provide a transfer material for imparting indicia to lms which will not be affected by the developing acton.

To accomplish the iirst mentioned object We produce a latent image on a part of the film by the application of pressure to the emulsion of the film at selected areas thereon and preferably in the presence of a tribo-luminescent material and/or absorber for halogens.

For attaining the second object we may employ as a transfer medium an alcohol or oil soluble dye which is insoluble and unaffected by water and aqueous alkaline solution.

The inventive features of the invention as shown in connection with a dental X-ray iilm packet which briefly described includes an envelope having a cover and in which a film is folded over one end of a lead sheet to form a tag protected from the light. A marking medium layer intermediate of the cover` and tag is responsive to pressure, as by a stylus or pencil, applied to the outer surface of the cover.

In the accompanying drawing showing, by way of example, one of many possible embodiments of the invention,

Fig. l is a plan of the packet, and

Fig; 2 is a cross-sectional view of the packet the section being taken along the line 2-2 of Fig. 1.

The packet comprises a usual photographic film I having a tag portion II folded or turned back over at least a part of the main portion of the film. A leaden sheet I2 is interposed between the main portion of the iilm and its tag so that exposure of the film to X-rays from below as shown in the drawing does not affect the tag. Adjacent to the exposed surface of the tag is a layer of a marking medium Ill for producing a substantially permanent marking on the developed lm and described in detail hereinafter. Above the marking medium layer is disposed thereon, and preferably covering the upper face of the leaden sheet, an opaque sheet of black paper or cover I5. The paper sheet may be opaque to X-rays although itis only necessary that it be opaque to the ordinary actinic light.

A backing sheet I6 of black paper transparent 10 Claims. (Cl. Z50-67) to X-rays and opaque t0 ordinary light is preferably disposed against the lower faceof the lm. The edge portions of the sheets and the lm are secured together by a Wrapper I8, described in Patent No. 2,277,364, proof against ordinary actinic light, and covering the sheets and lm but preferably leaving an opening I9 at least in the region of the marking medium to lay bare the sheet I5. By means of a pointed instrument such as a stylus or pencil pressure is appliedthrough the sheet I5 to the marking medium to form indicia. If the sheet I5 isof contrasting color with vrespect to the pencil the the indicia may appear visible onthe sheet I5 as at 20.

The marking medium layer I4 may comprise a binder, such as gelatin, for a tribe-luminescent material or for a halogen absorber or for water insolublecolor.

A number of tribo-luminescent materials are known. All of these materials have the characteristic of emitting light when rubbed, scratched, cracked, struck, cleaved, or crushed. Advantage of these characteristics are taken when the layer I4 of the material is subjected to pressure by a stylus on the cover I5 which transmits the pressure to the tribe-luminescent material adjacent the tag end I I of the photographic film. Thus Wherever pressure is applied to the layer I 4, such as by the stylus acting through the medium of the cover, a glow comparable to the indicia will be produced.` This glowis more or less transient but of sufficient duration and intensity to light strike the tag and produce a latent image on the film. The latent imageV remains unaffected until development for the cover I5 is still intact and no amount of ordinary light can affect the lm. The layer I4 may be coated directly onto the tag II or on the covery I5, lor may be formed as a thin sheet to be disposed between the cover and tag. Y Y

The binder for the tribe-luminescent material may be such as gelatin, isinglass, zein, glue, methyl cellulose, ethyl cellulose, soaps `and starches.

As tribo-luminescent materials, the following 1may be used either singly or taken in combinaion. Y

Calcium salts e. g. CaS 0.003% to 0.1% of heavy metal salts; Y Y- u Arsenous trioxide (As2Os);

Uranium nitrate (UO2(NO3)2); Y'

Zinc sulphide (ZnS) -(containing impur' ies of heavy metal salts, e. g. Wurtzit);

matter;

Manganous sulphide (Mns):

...stannous `saltsor of titanium salts lZinc sulphide Vore Sphalerite (preferably from Horn `Silver Mine, Utah).

Certain articallyprepared compounds exhibit triboluminescence of varying extent according zto modes of preparation. For example a zinc suldepreparedlby calcining 100 g. zinc caribonate, '30:grsu'lphur and "0.5g. magnesium oxide fori30 "minutes-at 1a temperature of about 300- 1500is a superiortriboluminescent material when glue is used'asthe binder.

The action of the tribo-luminescent material .maybe enhanced by the vaddition of a 'reducing A -`agent or halogen absorber, such vas sodium nitrite or hydrazine salts, to the layer I4.

The entire action is not completely understood but appears to be more than a mere reduction of 'theghalide bythereducing agent and it is prob- Vable that the lightV emitted vduring the luminescence has a greater range 'of activity than the `simple .action .of the reducing agent brought .into contact with emulsion at a relatively small Vnumber lof points.

"lf lthe emulsion ,ofthe hlm is especially rich insilver halideand the layer I4 contains the reducing :agent or :absorber or hydrazine salts it is possible to dispense with the tribo-luminescent material. It `iseven Vpossible that the reducing vagent pand layer kI4 may be omitted but with *lesssatisfactory results. It therefore appears'that ipressurealoneon arich emulsion is Vsuicient'toproduce a latent image without the pneedforistencils or transfer sheets vheretofore employed- `1It is 'preferablehoweven toemploy the reduc- "ing agent when V,no tribo-luminescent material isused. In such instances the binder or vehicle for thereducer may'fbeanysuitable semi-solid kmaterial inert to` the reducer and emulsion such nasa-mixture'of gelatin and glycerine or gelatin f and adsorbitol.

Stannous chloride may be employed both as a reducer and tribe-luminescent material.

'The foregoing structures Yand composition depend on the reduction of the halide to produce developed indicia onan undevelopedbackground. Sometimes, as when positive vprints 'are to be made, it may be -desirable'to develop `vthe vbackground and leave the indicia undeveloped. In such instances the layer I4 Vmaybe of a slightly tacky consistency, containingan oil-and-.a'lcohol soluble lightblocking dye insoluble in water and alkalis, and the layer adhered to the'cover I5.

vwith solvent subsequent to developing if desired.

4as polyvinyl alcohol, zein or glue.

The body of the layer may be tallow, waxes, resins (e. g. elemi) methyl abretate and suitable solvents to give the necessary tackiness such as chlorinated hydrocarbon, aromatic hydrocarbons, or alcohols. In use, the pressure of the stylus causes .a transfer of the dye and its tacky .vehicle from the cover tothe lm. The cover I5 is then removed so that light may strike the background of the indicia with the latter protected. The transferred indicia may be removed The layer I4 of marking medium is preferably made up of sphalerite and a small amount of powdered friction material or ne abrasive intimately mixed together so that when pressure `is applied'tozthe layer a particle of the sphalerite will .be Vrubbed or scratched by the abrasive in a crunching action. The two materials may be bound together lightly by a suitable binder such Of course other tribo-luminescent materials may be employed in la like manner. Such a layer may be formed by dispersing the tribe-luminescent material and abrasive, such as powdered glass, in a `solution of the binder and spreading the dispersion on the cover I5 and allowing the lm to dry. Water may be used as the solvent for polyvinyl alcohol and glue while alcohol may be used for zein. The abrasive or friction material need not be as hard as 'glassor even the sphalerite itself for ltribo-luminesoence is obtained by merely `drawing the fingernail across a crystal of the sphalerite.

The invention claimed'is:

1. An X-ray film packet comprising a lead sheet; a photographic film folded over one end of the sheetand forming a tag lying on the sheet and an image receptive portion adjacent and under the sheet; a cover for the sheet and tag; a layer of tribe-luminescent material intermediate of the cover and tag, and means for holding the sheet, tag, layer and cover together.

2. A packet as in claim 1, said tribe-luminescent material'being phenetsal.

3. An X-ray film packet comprising a lead sheet; `a photographic film disposed Abelow the sheet andhaving an end portion of the film folded up and over an Yend fof the lead sheet and 'forming a tag lying on the top face of the sheet,

the lower face of the portion of the lm beneath the sheet being covered with a covering of material opaque to normal light and transparent Ato Xrays; a layer of tribo-luminescent material on the u pper face of the tag; .a cover opaque to normal lightcovering the upper face of thelayer of vtribo-luminescent material, vand means for L'holdingsaid'sheet, film, covering and cover toslm'having one end portion folded backwardly parallel with the vmain portion of the'lm to form va tag; a layer of tribu-luminescent material .on Vthe outer face ofthe tag; .a leaden sheet intermediate ofzthetag and said main portion `where- :by whentheiouterfface of the lmain .portion is normally exposed to X-rays said rays will not penetrate through the sheet to the tag.

7. A photographic film device comprising a photographically sensitive sheet; a second sheet exteriorly exposed and opaque to normal natural light covering said sensitive sheet to protect the latter from ordinary light; and tribo-luminescent material intermediate of the two sheets.

8. A laminated photographic image recorder comprising a photographically sensitive sheet; a second pressure transmitting sheet exteriorly exposed and opaque to light and covering the sensitive sheet to protect same from the light; and a layer of tribe-luminescent material intermediate of the said sheets and free from opaque matter between the tribe-luminescent material and the sensitive sheet whereby pressure applied to the exposed face of the opaque sheet will be transmitted to said layer which will glow under the inuence of the pressure and form an image on the sensitive sheet at points corresponding to the points of application of the pressure.

9. In an X-ray packet, a leaden sheet, a photographic lm disposed below the sheet and hav ing an end portion of the film folded up and over an end of the leaden sheet and forming a tag lying on the top face of the sheet, the lower face of lm beneath the sheet being covered with a covering opaque to normal light and transparent to X-rays; a top opaque cover for the outer face of tag portion and a layer of transfer material between the top cover and the tag portion. 10. In an X-ray packet as in claim 9, said transfer material being composed of a tacky binder and an oil-soluble dye opaque to normal light, the binder being insoluble in water and in alkali.

WILLIAM HEINECKE.

SAMUEL A. HERMAN.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS OTHER REFERENCES General College Chemistry by J. A. Babor, published by T. Y. Crowell Co., N. Y., 1936, page 387. 

